System and method for a multi-tenant datacenter with layer 2 cloud interconnection

ABSTRACT

Provided is a system and method for a multi-tenant datacenter with layer 2 cloud interconnection. More specifically the multi-tenant datacenter includes a plurality of physical client systems in a first datacenter each physical client system having a set of physical infrastructure resources. A first cloud computing environment is also in the first datacenter, and coupled to the physical client systems by OSI Layer 2. The first cloud computing environment thereby virtually extending the physical infrastructure resources of each physical client system. An associated method of providing a multi-tenant datacenter with layer 2 cloud interconnection is also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/356,555 filed Jan. 23, 2012, published as US2013/0188512,now U.S. Pat. No. ______. This continuing application claims the benefitof U.S. patent application Ser. No. 13/356,555.

FIELD OF THE INVENTION

The present invention relates generally to systems and methods forflexible network infrastructure, and more specifically to a multi-tenantdatacenter with Layer 2 cloud interconnection.

BACKGROUND

Computer systems, and more specifically networked computer systems are acenter point of modern society. Advances in production andminiaturization have permitted the production of increasingly fasterprocessors and larger data storage.

Commerce, and indeed business in general is highly reliant on networkedcomputer systems for nearly all aspects of business activity, such asbut not limited to offering products for sale, maintaining accountrecords, analyzing data, etc. . . . . Yet, the needs for resources mayand often do change from time to time.

Networks exist in a variety of forms, from the vast and expansive natureof the Internet to the small local area network of a company or homesetting. Whereas it was once commonplace to provide all desired computerresources within one physical system, networking systems permit agreater flexibility in adaptively balancing resources and scaling tomeet needs. Network connection and integration requires an ability forthe elements, e.g. systems, of the intended network to find andcommunicate with each other.

The Open System Interconnection model, also referred to as the OpenSource Interconnection model or more simply the OSI model, is a productof the Open System Interconnection effort at the InternationalOrganization for Standardization, and more specifically is aprescription of characterizing and standardizing the functions of acommunication system in terms of seven abstraction layers of concentricorganization—Layer 1 the physical layer, Layer 2 the data link layer,Layer 3 the network layer, Layer 4 the transport layer, Layer 5 thesession layer, Layer 6 the presentation layer, and Layer 7 theapplication layer.

Each layer is generally known as an N Layer. At each layer, twoentities, i.e., N-entity peers, interact by means of the N protocol bytransmitting protocol data units or “PDU”. A Service Data Unit “SDU” isa specific unit of data that has been passed down from one layer toanother, and for which the lower layer has not yet encapsulated into aPDU. Moreover the PDU of any given layer, Layer N, is the SDU of thelayer below, layer N-1. In other words, the SDU is the payload of agiven PDU.

Transfer of an SDU between layers is therefore a matter of encapsulationand is performed by the lower layer in adding appropriate headers and orfooters to the SDU such that it becomes a PDU. These headers and orfooters are part of the communication process permitting data to getfrom a source to a destination within any network.

Briefly, Layer 1, the physical layer defines the electrical and physicalspecifications of the device and the communication medium, e.g., coppercable, optical cable, wireless, etc. Layer 2, the data link layer,provides the functional and procedural means to transfer data from oneentity to another, and to possibly correct errors that may occur in thephysical layer. The data is arranged in logical sequences known asframes.

Layer 3 is the network layer and provides the functional and proceduralmeans of transferring variable length data sequences from a source onone network to a destination host on a different network. Routersoperate at this layer and make the Internet possible by properlyhandling the interconnections and handoffs between different networks.Layer 4 is the transport layer responsible for data transfer between endusers and the reliability of a given link through flow control,segmentation/desegmentation and error control.

Layers 5, 6 and 7 as the Session, Presentation and Application layer aresuccessively higher and closer to the user and subsequently further andfurther away from the physical layer. The greater the number oftransfers between layers to accomplish any given task, the greater thecomplexity, latency and general opportunity for error.

Indeed within a typical local area network (LAN), wherein the systemsare indeed part of the same network, the communication of data transferis generally accomplished at the Layer 2 level. However, when joiningone LAN to another, or to a wide area network (WAN), the addresses ofthe LAN may be meaningless or perhaps even duplicative of otheraddresses in other LANs and as such the translation to Layer 3 is thegenerally accepted method for maintaining harmony in communication.

While this is a viable option, and indeed the existence of the Internetdemonstrates overall functionality, it does often come with overheadcosts and burdens of complexity. For example, whereas a database withina LAN may be communicated with via Layer 2 and thereby enjoy enhancedintegration as a networked component, accessing a similar database overLayer 3 requires Internet Protocol “IP” address translation, or othersimilar transformation which by it's vary nature requires theoriginating system to be configured for, and perhaps engage inappropriate measures for proper identification, and addressing of datato and from the remote database as would not be otherwise required witha LAN based database. For example the LAN systems may be on one networkor VLAN and the remote database is part of another network or VLAN—thedifferences requiring at the very least a router to adjust and accountfor the differences in network identity and configuration.

Indeed, while remote services do provide a lower cost option to thedirect acquisition of hardware and thereby permit enhanced scalabilityof resources in response to needs, the remote services as offered to aplurality of needy parties are not perceived by each party simply as anextension of his or her existing resources.

One form of remote service is that of cloud computing, wherein acollection of physical systems provide both physical and virtualizedresources. Although gaining in popularity, cloud computing and theintegration of these resources is performed at Layer 3 so as to permitthe generally accepted methodologies of IP protocol translations toinsure proper segregation of data.

Moreover, as many LANs are configured with default options it is verycommon for multiple end users to have the same local IP addresses withintheir various networks. For connection to and utilization of atraditional cloud environment network address translation must beemployed—a requirement that is often beyond the skills and capability ofthe end user. When the needs for such resources are dynamic, suchcontinual adjustments and additions through Layer 3 IP addresses can betaxing in terms of time, costs, and possible error among other factors.

Further, the resources of a cloud environment are also generally limiteddue to one or more physical constraints. Although perhaps expandable toa point, such expansion cannot generally be achieved in real time as atsome point additional physical systems must be installed, configured andintegrated. And again, once such systems have been integrated, if theneed for resources diminishes they cannot easily be taken out of usewithout again physical interaction.

Moreover, although cloud computing does provide an improvement in manyways over previous options for expansion and contraction of resources tomeet needs, it is not without it's own set of challenges anddifficulties.

It is to innovations related to this subject matter that the claimedinvention is generally directed.

SUMMARY

Embodiments of this invention provide a system and method for amulti-tenant datacenter with Layer 2 cloud interconnection.

In particular, and by way of example only, according to one embodimentof the present invention, provided is a multi-tenant datacenter,including: a plurality of physical client systems in a first datacentereach physical client system having a set of physical infrastructureresources; a first cloud computing environment established in the firstdatacenter, and coupled to the physical client systems by OSI Layer 2,the first cloud computing environment thereby virtually extending thephysical infrastructure resources of each physical client system.

In another embodiment, provided is a method for providing a multi-tenantdatacenter, including: establishing within a first datacenter a firstcloud computing environment; locating at least one physical clientsystems in the first datacenter, each physical client having a set ofphysical infrastructure resources; and coupling the at least onephysical client system to the first cloud computing environment by OSILayer 2, the OSI Layer 2 coupling virtually extending the physicalinfrastructure resources of each physical client system.

In yet another embodiment, provided is a method for providing amulti-tenant datacenter, including: establishing within a firstdatacenter a first cloud computing environment; locating a plurality ofphysical client system in the first datacenter, each physical clientsystem having a set of physical infrastructure resources; and uniquelyidentifying data traffic as between each client system and the firstcloud computing environment by a plurality of OSI Layer 2 tags as uniqueidentifiers permitting unique identification for each client system ofat least one host and a customer.

Still further, in another embodiment, provided is a method for providinga multi-tenant datacenter, including: establishing within a firstdatacenter a first cloud computing environment having first physicalresources and first virtual resources; establishing within a seconddatacenter a second cloud computing environment having second physicalresources and second virtual resources; and coupling the first cloudcomputing environment to the second cloud computing environment by OSILayer 2.

BRIEF DESCRIPTION OF THE DRAWINGS

At least one system and method for a multi-tenant datacenter with Layer2 cloud interconnection will be described, by way of example in thedetailed description below with particular reference to the accompanyingdrawings in which like numerals refer to like elements, and:

FIG. 1 illustrates a conceptual view of a multi-tenant datacenter withLayer 2 cloud interconnection in accordance with at least one embodimentof the present invention;

FIG. 2 illustrates a conceptual view of multiple multi-tenant datacenterwith Layer 2 cloud interconnection interconnected in accordance with atleast one embodiment of the present invention;

FIG. 3 illustrates yet another conceptual view of multiple multi-tenantdatacenter with Layer 2 cloud interconnection interconnected inaccordance with at least one embodiment of the present invention;

FIG. 4 illustrates a high level flow diagram depicting at least onemethod for a multi-tenant datacenter in accordance with at least oneembodiment of the present invention;

FIG. 5 is illustrates a more refined flow diagram depicting at least onemethod for a multi-tenant datacenter in accordance with at least oneembodiment of the present invention;

FIG. 6 illustrates an exemplary frame and its Layer 2 tagging forcommunication between a client system and a cloud system within a commondatacenter in accordance with at least one embodiment of the presentinvention;

FIG. 7 illustrates yet other exemplary frames and their Layer 2 taggingfor communication between a client system and a cloud system within acommon datacenter in accordance with at least one embodiment of thepresent invention;

FIG. 8 illustrates yet other exemplary frames and their Layer 2 taggingfor communication between a client system and a cloud system indifferent physical datacenters in accordance with at least oneembodiment of the present invention; and

FIG. 9 is a block diagram of a computer system in accordance withcertain embodiments of the present invention.

DETAILED DESCRIPTION

Before proceeding with the detailed description, it is to be appreciatedthat the present teaching is by way of example only, not by limitation.The concepts herein are not limited to use or application with aspecific of system or method for a multi-tenant datacenter with OSILayer 2 cloud interconnection. Thus, although the instrumentalitiesdescribed herein are for the convenience of explanation shown anddescribed with respect to exemplary embodiments, it will be understoodand appreciated that the principles herein may be applied equally inother types of systems and methods for multi-tenant datacenters.

Turning now to the drawings, and more specifically FIG. 1, illustratedis a high-level diagram of a multi-tenant datacenter with OSI Layer 2cloud interconnection (“MTDC”) 100 in accordance with certainembodiments.

Moreover, MTDC 100 has a plurality of physical client systems 102, ofwhich client system 102A corresponding to C1, client system 102Bcorresponding to C2 and client system 102C corresponding to Cn areexemplary. These client systems 102 are located within a firstdatacenter 104. It is understood and appreciated that although depictedas single elements, each client system 102 may indeed be a racked set ofphysical components interconnected as a Local Area Network, LAN. Furthereach client system 102 has a set of physical infrastructure resources106, such as but not limited to one or more processors, main memory,storage memory, network interface devices, long term storage, networkaccess, etc. . . .

A first cloud computing environment, hereinafter first cloud 108 isestablished in the first datacenter 104 by one or more physical and/orvirtual computer systems 110, of which systems 110A-110D are exemplary.

More specifically, first cloud 108 is established at least in part byphysical computer systems. Although improvements in manufacturing havereduced the costs associated with physical components and systems, andtherefore also reduced the cost of the programmable machine, in manyinstances the total resources of a machine are not utilizedcontinuously.

In light of this, in many situations it has been found that a physicalmachine can be adapted to provide a plurality of virtualmachines/systems—each an efficient, and functional equivalent of a realphysical machine. Each virtual machine/system can provide a completesystem platform that supports the execution of a complete operatingsystem and any associated applications.

Because one physical programming machine can support multiple virtualmachines/systems, the cost benefits of utilizing virtual machines overindividual physical machines can be advantageous. In general, eachvirtual machine/system is an emulation of a physical machine/system,including a virtualization of the physical components, such as storagedevices, network devices, processors and the like. Systems 110A, 110Band 110D are physical systems, and 110C has been shown in dotted outlineto indicate that it is a virtual system, provided by physical system110B.

As used herein the first cloud 108 is understood and appreciated to be ahighly scalable and dynamic environment of computer resources andservices that can be provided to customers, specifically the clientsystems 102. In other words the first cloud 108 is structured andarranged to provide Infrastructure as a Service.

Advantageously, the first cloud 108 is coupled to the client systems 102by OSI Layer 2. As such the first cloud 108 thereby virtually extendsthe physical infrastructure of the resources of each client system 102.And, as this extension is accomplished at OSI Layer 2, the clientsystems 102 perceive the extended infrastructure resources as beingelements of their network.

It is to be understood and appreciated that the coupling by Layer 2 istruly by Layer 2 and not as a component of a Layer 3 interaction. Asnoted above and as will be appreciated by those skilled in the art, OSILayer 2 is the data link layer. At Layer 2, the exchange of data occursthrough the transmission of Frames. Although Frames can and arecomponents of Packets which are utilized at OSI Layer 3, the transfer ofFrames at Layer 2 occurs without reliance on Packets at Layer 3.Moreover, although Packets and Frames are both packages of data movingthrough a network, Packets are specifically and fundamentally at OSILayer 3—the network layer—and by it's very nature is dependent on IPProtocol. The transfer of Frames at Layer 2 can and often is distinctfrom the transfer of Packets at Layer 3. With respect to the presentinvention, the coupling at Layer 2 as between the first cloud 108 andthe client system 102 is an event prior to an OSI Layer 3 connection. Asis further set forth below, as the present invention couples at Layer 2,the present invention permits overlapping VLANS and IP address rangeswhich is problematic at Layer 3.

In other words, the client system 102, generally consisting of a rack ofcomponents coupled as a LAN enjoys the resources of the first cloud 108as if the provided resources were indeed part of the client system'sLAN. This is conceptually indicated by dotted extension 114 of cloudcomputing environment 108.

The coupling of the client systems 102 and the first cloud 108 isachieved through the physical connection of a data channel for thetransfer of data frames. This physical connection of a data channel isan OSI Layer 1 interconnection, e.g., wire, fiber, wireless or otherappropriate physical data channel.

The frame is a digital data transmission unit or data packet. In generala frame has control data used to deliver the packet and payload data. AtOSI Layer 2, these frames consist of a preamble, a destination MediaAccess Control address (MAC address), an origin MAC address, zero ormore tags, the payload data and a gap. FIG. 6 presents example frame600, showing preamble 602, a destination MAC address 604 correspondingto system 110A, an origin MAC address 606 corresponding to client system102A, a payload 608, and a gap 610. These frames as provided by theclient systems do not contain the IP address of the destinationresource. Similarly, these frames as provided by a first cloud 108system for return to an associated client system 102 do not contain theIP address of the destination client.

This physical connection permitting OSI Layer 2 interconnection in MTDC100 between the client systems 102 and the first cloud 108 should not beconfused with more traditional cloud environments wherein clientsconnect to a cloud by way of some data channel but data exchange isknowingly and intentionally handled at OSI Layer 3 or above. Suchconnections do not seamlessly and transparently blend the client systems102 and first cloud 108 systems 110 together as is achieved in MTED 100.Moreover, at OSI Layer 3 the transfer of data elements is by Packets,and is dependent upon the IP Protocol. As such the IP address cannotoverlap—if they do, then the packet routing system will have a problemin attempting to properly route packets to the correct system and theuse of tags at Layer 3 will not resolve the problem. Even if Frameswithin the Packets are tagged, the fundamental reliance upon IP Protocolat Layer 3 dictates that overlapping IP ranges are still problematicregardless of whether or not some element of frame tagging is attempted.On the other hand, because the present invention utilized Layer 2, andthe coupling is prior to an OSI Layer 3 connection, the problematicissues of IP range overlap at Layer 3 are simply not an issue.

With respect to FIG. 1, for at least one embodiment, the client systems102, such as client system 102A are connected directly to a system 110,as shown by L1/L2 connection link 112, indicating an OSI Layer 1 or OSILayer 2 link. Although viable, with a large plurality of client systems102, such direct connection permits limited scalability. Moreover, forat least one alternative embodiment, the client systems 102 are coupledto the first cloud 108 by at least one switch 116. These connections areOSI Layer 2 connections as indicated by the L2 links 112′.

The use of the switch 116 is quite specific and distinct from the use ofa router. A router is intended for traditionally interconnectingdifferent networks, e.g., a Level 3 operation. A switch on the otherhand is intended to connect computing devices together within one LAN.Each client system 102 is connected to the switch 116 and a map 118 isestablished within the switch 116 to properly interconnect each clientsystem 102 with the physical or virtual system 110 providing theintended infrastructure resources. For ease of illustration anddiscussion, this map 118 is conceptually shown as solid and dashedconnections as between the ports 120 to which the client systems 102 areconnected and the ports 122 to which the physical or virtual systems 110are connected.

As indicated above, the coupling of the client systems 102 to the firstcloud 108 is by the transfer of frames over the physicalinterconnection. To achieve the transparent extension of the clientsystem 102 infrastructure resources, for at least one embodiment aplurality of OSI Layer 2 tags are employed with each frame. These OSILayer 2 tags advantageously permit the identification for each clientsystem 102 of a host system and a customer system. Further, these OSILayer 2 tags are employed transparently by the MTDC 100 such that theclient systems 102 advantageously are permitted to operate without needfor purposeful transformation or adjustment to their respective LANenvironments for participation in the first cloud 108. Again, the use ofOSI Layer 2 tags and the transfer of Frames at OSI Layer 2 as distinctfrom OSI Layer 3 Packets is a distinct and advantageous component ofMTDC 100.

In other words client system 102A may have an IP range set to the rathertypical default of 192.168.0.X as may client system 102B. For atraditional cloud computing environment these default IP ranges couldpose a problematic issue for with the overlapping ranges proper dataintended for a system identified as 192.168.0.50 as part of clientsystem 102A could be inadvertently provided to a system identified as192.168.0.50 as part of client system 102B.

Likewise if multiple clients established Virtual local area networks, orVLANs, as default settings are often maintained, and or random selectioncould still permit overlapping ranges, errors in network trafficmanagement could occur. As MTDC 100 advantageously employs OSI Layer 2tagging and is not reliant upon IP addresses, these issues areirrelevant and each client system 102 is permitted to operate withoutinterference.

For at least one embodiment, the OSI Layer 2 tags employed are Q tags asdefined by IEEE 802.1Q. As the MTDC 100 is employing OSI Layer 2 tags toat least identify a host and customer, two (2) Q tags are generallyemployed at a minimum, known as QinQ tagging. More specifically, IEEE802.1Q is understood and appreciated as a standard for VLAN tagging.With IEEE standard 802.1ad, double-tagging can be achieved which permitsmixing traffic from multiple client systems 102 that have already beentagged.

To permit the QinQ tagging, in at least one embodiment of MTDC 100, twoswitches 116 may be connected in series to permit the double tagging.For at least one alternative embodiment, an enhanced switch 116 isemployed that is structured and arranged to permit double Q tagging.With respect to MTDC 100 as shown in FIG. 1, when a frame enters a port,e.g., ports 120 from the client systems 102 or ports 122 from the firstcloud 108 systems 110, a tag is added to represent the VLAN membershipof the frame's port and the second tag is added to represent the VLANmembership of the frame's destination port.

With respect to the exemplary frame 600 shown in FIG. 6, for the sake ofexample “A” series tags have been adopted to identify frames forassociation to client system 102A. As such, Tag1—the host tag 612—isshown as Q-A100 and Tag2—the customer tag 614—is shown as Q-A200.

Moreover, for at least one embodiment, an element of the OSI Layer 2coupling of the client systems 102 to the first cloud 108 is the mappingof the OSI Layer 2 tags such that switch 116 properly interconnects theclient systems 102 with the cloud 108, and more specifically the systems110 within the first cloud providing the extended infrastructure. For atleast one embodiment, the mapping process includes defining for eachclient system 102 the host and customer tags, and may well includedefining additional tags which may be used, but are not limited to,identification of the datacenter 104, i.e. cloud 108, itself to permitproper interconnection of multiple instances MTDC 100. The taggingprocess is further discussed below in in connection with describing atleast one method for providing MTDC 100.

In at least one embodiment additional OSI Layer 2 tags are alsoemployed, such as VPLS, MPLS tags, Segment ID Layer 2 tags and or GlobalVLAN Layer 2 tags. Moreover, in varying embodiments, the OSI Layer 2tags employed are selected from the group consisting of QinQ tags, MPLStags, VPLS tags, Segment ID tags, Global VLAN tags and combinationsthereof. The use of multiple OSI Layer 2 tags can permit increasedscalability as well as the ability to interconnect multiple MTDC 100locations advantageously at OSI Layer 2. Indeed, an additional switch124 is shown with a OSI Layer 2 connection to switch 116. Switch 124 isstructured and arranged to permit interconnection of this first instanceof MTDC 100 with one or more second instances of MTDC 100 as suggestedby dotted interconnection lines 126 and as further described below withrespect to FIG. 2.

Moreover, the use of Layer 2 tags selected from the group consisting of,but not limited to, Q tags, QinQ tags, MPLS tags, VPLS tags, are to beunderstood and appreciated as options for one or more specificembodiments, and not as limitations. Indeed other current and developingprotocols that permit Layer 2 extension are understood and appreciatedto fall within the present teachings for a multi-tenant datacenter withOSI Layer 2 could interconnection.

To summarize, for at least one embodiment the MTDC 100 consists of aplurality of physical client systems 102 in a first datacenter 104, eachphysical client system 102 having a set of physical infrastructureresources 106. A first cloud 108 is also established in the firstdatacenter 104. The first cloud 108 is coupled to the physical clientsystems 102 by OSI Layer 2, the first cloud 108 thereby virtuallyextending the physical infrastructure resources 106 of each physicalclient system 102.

In addition, for at least one embodiment the MTDC 100 consists of aplurality of physical client systems 102 in a first datacenter 104, eachphysical client system 102 having a set of physical infrastructureresources 106. A first cloud 108 is also established in the firstdatacenter 104. The first cloud 108 is coupled to the physical clientsystems 102 by OSI Layer 2 as the physical connection of a data channelfor the transfer of data frames distinct from OSI Layer 3communications, the first cloud 108 thereby virtually extending thephysical infrastructure resources 106 of each physical client system102.

Further, for at least one embodiment the MTDC 100 consists of aplurality of physical client systems 102 in a first datacenter 104, eachphysical client system 102 having a set of physical infrastructureresources 106. A first cloud 108 is also established in the firstdatacenter 104. The first cloud 108 is coupled to the physical clientsystems 102 by OSI Layer 2, prior to an OSI Layer 3 connection, as thephysical connection of a data channel for the transfer of data frames,each frame having a plurality of OSI Layer 2 tags permitting at leasttwo client systems to have overlapping VLANs and or overlapping IPaddress ranges, the first cloud 108 thereby virtually extending thephysical infrastructure resources 106 of each physical client system102.

FIG. 2 conceptually illustrates a further embodiment of the presentinvention wherein multiple MTDC 100 installations are interconnected.More specifically, in FIG. 2, MTDC 100 is generally shown reproduced ata smaller scale.

An additional installation of multi-tenant datacenters with OSI Layer 2interconnection is shown as MTDC 200 having a second cloud computingenvironment, hereinafter second cloud 208 in a second datacenter 204,also housing at least one client system 202. The second cloud 208 isestablished in the second datacenter 204 by one or more physical and/orvirtual computer systems 210. Moreover, with respect to this descriptionit is understood and appreciated that MTDC 100 refers generally to thesingle multi-tenant datacenter as shown in FIG. 1, however MTDC 100 mayalso refer to embodiments having multiple distinct datacenters that areinterconnected. To the extent possible distinct references, such as MTDC200 and MTDC 250 are used to help distinguish between specificinstances, but in the absence of such distinction a general reference toMTDC 100 may be applied to the collective whole of interconnecteddatacenters.

As with the client systems 102 of MTDC 100, each client system 202 ofMTDC 200 has a set of physical infrastructure resources 206. As theclient system 202 is coupled to the second cloud 208 by OSI Layer 2, thesecond cloud 208 virtually extends the physical infrastructure resourcesof each physical client 202. For at least one embodiment the coupling ofthe client systems 202 to the second cloud 208 is performed with aswitch 212.

A third instance of a multi-tenant datacenter with OSI Layer 2interconnection is also shown as MTDC 250, and for ease of illustrationand discussion is conceptually shown as a cloud. It is understood andappreciated that MTDC 250 comprises substantially the same componentsand elements of configuration as shown and described with respect toMTDC 100 and MTDC 200. Additional instances of MTDC may of course alsobe provided but are not shown for ease of illustration and discussion.As with the use of OSI Layer 2 tags to uniquely identify theinterconnections of client systems 102 and the first cloud 108, OSILayer 2 tags are used to uniquely identify each cloud, e.g., first cloud108, second cloud 208, and the cloud of MTDC 250, not shown. Moreover,in at least one embodiment each datacenter, i.e., cloud has it's ownpre-defined OSI Layer 2 tag or range or OSI Layer 2 tags, these tagsprovided in the map established with each switch, e.g., switch 116, 212in each MTDC, e.g., MDTC 100, 200.

With respect to FIG. 2, MTDC 100, MTDC 200 and MTDC 250 are shown asbeing interconnected by switches 124, 220 and 222 which permit OSI Layer2 interconnection over dedicated lines 224, 226 and 228. OSI Layer 2interconnection of MTDCs is advantageous as each cloud, e.g., firstcloud 108 and second cloud 208 of each interconnected MTDC isindistinguishable by the plurality of client systems 102, 202.

Moreover, the infrastructure resources of the first cloud 108 can beutilized by clients systems 204 in the second datacenter 204 as if theywere part of the first cloud, and vis-a-versa. Indeed the addition ofadditional MTDCs such as MTDC 250 advantageously provides furtherinfrastructure resources to the overall interconnected cloudenvironment.

In short the cloud environment itself is advantageously dynamicallyadjustable as the OSI Layer 2 interconnections between the variousphysical datacenters permit the entire cloud environment to bestructured and arranged as a collective whole. Such dynamic adjustmentmay advantageously provide greater efficiency in response time tochanging client system demands, upgrades and overall system maintenance,as well as overall transparent reassignment of infrastructure resourcesas well as other benefits.

In some embodiments due to cost constraints or other factors it may bedesirable to use existing network providers to link one or more MTDCs.Such a configuration is shown in FIG. 3, where switches 124, 220 and 222have been replaced by routers 300, 302 and 304. As shown, dedicated link226 is still provided between MTDC 100 and MTDC 250, however networkprovider link 306 operating at ISO Layer 3 is in place between MTDC 100and MTDC 200. Likewise network provider link 308 operating at ISO Layer3 is in place between MTDC 250 and MTDC 200.

The introduction of a network provider links 306 and 308 as a means forinterconnection between MTCDs is substantially immaterial. The clientsystems, e.g., clients 102 and 202 are not aware of the network providerlinks 306 and 308. More specifically, the client systems 102 and 202 arepermitted to continue operation and use of the interconnected cloudresources as part of their own respective LANs. Although an IP addressmay be added to the frame, the addition is performed by the outboundrouter, e.g., router 300 and removed upon receipt by the inbound router,e.g., router 302—the addition and removal being transparently performedfrom the perspective of the client systems 102, 202 and the respectivesystems 110, 210 virtually extending the infrastructure resources.

In general, where multiple clients share space and facility resourcesthe costs per client are generally reduced from what would otherwise berequired in the support of a single client. As such, for clients withinvestments in physical computer resources integration of thoseresources into MTDC 100 advantageously permits dynamic adaptation ofinfrastructure as a service in a multi-tenant environment that is nototherwise available.

It is also understood and appreciated that the features and benefits ofMTDC 100 alone or interconnected with other MTDCs, e.g., MTDC 200 arenot limited to physical client systems 102. For at least one embodimentof MTDC 100, an entirely virtualized client system is established withinMTDC 100. For such an embodiment, the virtualized client system enjoyssubstantially the same advantages of dynamic scalability, permittedoverlapping IP ranges, permitted overlapping VLANs and other benefitsprovided to the physical client systems 102. Should one or more virtualclient systems be established in an embodiment consisting of multipleinterconnected MTDCs, e.g., at least MTDC 100 and 200 the advantagesprovided to the virtualized client system are further extended as withthe physical client systems 102 and 202.

FIG. 4 conceptually illustrates a high level flow diagram depicting atleast one method 400 for a multi-tenant datacenter, e.g., MTDC 100, andFIG. 5 conceptually illustrates a more refined method 500 for amulti-tenant datacenter, e.g., MTDC 100 or interconnected plurality ofMTDCs. It will be understood and appreciated that the described methodsneed not be performed in the order in which it is herein described, butthat this description is merely exemplary of one method for providingMTDC 100.

At a high level, method 400 may be summarized and understood as follows.For the illustrated example, method 400 commences with establishing afirst cloud 108 in a first datacenter 104, block 402 and see FIG. 1. Atleast one physical client system 102 is then also located within thefirst datacenter 108, block 404. As shown and described above withrespect to FIG. 1, each physical client system 102 has a set of physicalinfrastructure resources 106.

The physical client 102 and first cloud 108 are then coupled by OSILayer 2, block 406. As shown in comparison of FIG. 1 to FIGS. 2 and 3,there can be one instance of MTDC 100 or a plurality of theminterconnected. Method 400 addresses this possibility with decision 408.For a first embodiment consisting of a single instance of MTDC 100(Multiple Clouds=No), method 400 moves to employing OSI Layer 2 taggingto uniquely identify all data frames, block 410.

For at least one embodiment, the OSI Layer 2 tagging is QinQ tagging,with the first Q tag identifying the host, block 412, and the second Qtag identifying the customer, block 414. In varying alternativeembodiments additional OSI Layer 2 tags may also be employed such as forexample VPLS and MPLS tags. Again, as noted above, the use of Q tags,QinQ tags, MPLS tags, VPLS tags, Segment ID tags, Global VLAN tags andcombinations thereof are exemplary of Layer 2 tags permitting Layer 2extension, and are not exclusive limitations.

Moreover, the use of Layer 2 tags selected from the group consisting of,but not limited to, Q tags, QinQ tags, MPLS tags, VPLS tags, Segment IDtags, Global VLAN tags are to be understood and appreciated as optionsfor one or more specific embodiments, and not as limitations. Indeedother current and developing protocols that permit Layer 2 extension areunderstood and appreciated to fall within the present teachings forLayer 2 tagging to uniquely identify all data frames.

The OSI Layer 2 tagging permits the dynamic extension of at least onephysical client system's physical infrastructure resources into thecloud computing environment, block 416. Again, it is the coupling at OSILayer 2 as opposed to the more common OSI Layer 3 and the distinct useof Layer 2 frames apart packets at OSI Layer 3 which advantageouslypermit the present invention to achieve this dynamic extension of atleast one physical client system's physical infrastructure resources,including the potential overlap of IP address rages and or overlappingVLANS. Network interconnection performed at OSI Layer 3 and reliant uponOSI Layer 3 can not achieve these advantages.

With respect to decision 408 and the evaluation of multiple clouds, forat least a second embodiment consisting of multiple instances of MTDC,e.g., at least MTDC 100 and MTDC 200 (Multiple Clouds=Yes), method 400moves to establishing at least one second cloud 208 in at least onesecond datacenter 204, block 418 and see FIG. 2.

As noted above, the first cloud 108 is coupled to the second cloud 208by OSI Layer 2, block 420. Moreover, the methodology of mapping MACaddresses and Q tags as employed for the OSI Layer 2 coupling of clientsystems 102 to the first cloud 108 is extrapolated and applied to couplethe first cloud 108 and the second cloud 208. As shown in FIG. 2, for atleast one embodiment this cloud to cloud coupling of multiple MTDCs isentirely OSI Layer 2.

However, for at least one optional environment as shown in FIG. 3 longhaul network provider links may be employed. For such an embodiment,transparent Layer 3 transformation is performed merely for the long haulcomponent of connection between physical datacenters, block 422. TheLayer 3 and IP component is not apparent to the client systems or thecloud supporting systems. With the resources virtually extended asindicated by block 416, method 400 continues as long as desired,decision 424.

Moreover, coupling the client systems 102 to the first cloud 108, asindicated by block 406 permits the clients and their associated cloudresources to appear as being on the same LAN, dotted oval 426. Inaddition, the OSI Layer 2 tagging, such as provided by the QinQ taggingof blocks 412 and 414 for the dynamic extension of the client resourcesinto the cloud as in block 416 advantageously permits multiple clientsto have overlapping IP and or VLAN settings without interference, dottedoval 428.

To summarize, for at least one embodiment a method 400 of providing MTDC100 consists of establishing within a first datacenter 104 a first cloud108. At least one physical client system 102 is also located within thefirst datacenter 104, each physical client system 102 having a set ofphysical infrastructure resources 106. The method 400 continues bycoupling the at least one physical client system 102 to the first cloud108 by OSI Layer 2, the OSI Layer 2 coupling thereby virtually extendingthe physical infrastructure resources 106 of each physical client system102.

An embodiment of a method 400 for providing MTDC 100 may also besummarized as establishing within a first datacenter 104 a first cloud108, and locating a plurality of physical client systems 102 in thefirst datacenter 108, each physical client system 102 having a set ofphysical infrastructure resources. The method continues by uniquelyidentifying data traffic as between each client system 102 and the firstcloud 108 by a plurality of OSI Layer 2 tags permitting uniqueidentification for each client system 102 of at least one host and acustomer.

FIG. 5 conceptually illustrates a more refined method 500 for amulti-tenant datacenter further illustrating the use of additional OSILayer 2 tags with respect to resources in different cloud computingenvironments 108.

Method 500 commences with establishing a first cloud 108 in a firstdatacenter 104, locating at least one physical client system 102 withinthe first datacenter 104 and coupling the client system 102 to the firstcloud 108, block 502.

Next, a second cloud 208 in a second datacenter 204 is established, atleast one physical client system 202 is located within the seconddatacenter 204 and the client system 202 and second cloud 208 arecoupled, block 504. MTDC 100 and MTDC 200 are then coupled, block 506.

For the example method 500, next is a query to determine if a clientsystem has multiple VLANs, decision 508. If the answer is NO, the method500 proceeds to apply OSI Layer 2 tags for each client connection forunique identification of all data frames, block 510. For at least oneembodiment, the OSI Layer 2 tagging is QinQ tagging, with the first Qtag identifying the host, block 512, and the second Q tag identifyingthe customer, block 514. In varying alternative embodiments additionalor alternative OSI Layer 2 tags may be employed, such as for exampleVPLS and MPLS tags.

Where indeed there are multiple VLANs, an answer of Yes for decision508, the method 500 proceeds to apply Level 2 tags to uniquely identifyeach VLAN for each client system 102. For at least one embodiment thisOSI Layer 2 tagging is QinQ tagging. Moreover, method 500 proceeds toselect a VLAN, block 516, apply the first Q tag identifying the host,block 518 and the second Q tag identifying the customer, block 520. Ifthere are more VLANs remaining, decision 522, the next VLAN is selected,block 524 and the process repeats until all VLANs have been uniquelytagged.

For proper delivery of the frame, the map of the predefined OSI Layer 2tags is consulted to determine the location of the resource. Withrespect to FIG. 1 and the above description, it is understood andappreciated that the map is an element of switch 116. With respect tothe multi MTDC configuration shown in FIGS. 2 and 3, each MTDC instancehas a switch, e.g., switch 212 of MTDC 200, which also a map table forthe pre-defined OSI Layer 2 tags.

FIGS. 6, 7 and 8 provide conceptual examples of this OSI Layer 2 taggingfor the unique identification each frame and are provided to furtherassist in appreciating the method of providing a multi-tenantdatacenter.

More specifically, FIG. 6 illustrates a frame as between C1, clientsystem 102A (having origin MAC address 57:89:6f:88:9d:c7), and physicalcloud system 110A (having destination MAC address 28:08:80:52:17:20) anda payload 608 “Happy”. For ease of illustration and discussion, the OSILayer 2 tags as employed have been illustrated conceptually in an easyto read and understand manner. Client system 102A has been assigned Aseries tags, and an appropriate Tag1 612 and Tag2 614 demonstrate this.For the sake of example, the IP ranges for the LAN of client system 102Amay be 10.20.30.0-50.

FIG. 7 illustrates two frames, 700 and 750. The first, illustrates aframe 700 as between C2, client system 102B (having origin MAC address04:7A:9e:a1:a3:41), and physical cloud system 110B (having destinationMAC address 6e:25:47:1f:9a:97). Frame 700 has the same basic structureas frame 600, a preamble 702, destination MAC 704, origin Mac 706, apayload 708 and a gap sequence 710. For frame 700 the payload 708 is“Grumpy”.

Client system 102B has been assigned B series tags as demonstrated byTag1 712 and Tag2 714. For the sake of example, the IP ranges for theLAN of client system 102B may be 10.20.30.20-80. As such, clearly thereis the possibility for overlapping IP addresses with client system 102Aand client system 102B, those between 10.20.30.20 and 10.20.30.50.However, as neither frame 600 nor frame 700 includes a tag forrepresentation of an IP address as specified by either the origin or thedestination, any overlapping of IP addresses is of no consequence andwill not interfere with the delivery of the frames.

As noted above, in at least one embodiment, the first cloud 108comprises at least one virtual machine which is structured and arrangedto provide infrastructure services to at least one client system 102.FIG. 7 also illustrates a frame 750 as between C2, client system 102B(having origin MAC address 04:7A:9e:a1:a3:41), and virtual cloud system110C (having destination MAC address 8a:02:28:11:2a:01) and a payload708 “Sneezy”.

As noted with respect to frame 700, client system 102B has been assignedB series tags. As such for this example Tag1 712′ for the host in frame750 is the same as Tag1 712 in frame 700. However, the customer in thisexample is different so Tag2 714′ is different. Moreover, for thepurposes of tagging frame 750 the nature of the destination system asbeing virtual is substantially irrelevant.

Returning to method 500 in FIG. 5, a query is performed to determine ifthe requested resource is within the current cloud, decision 526. Forthe example frames 600, 700 and 750 the answer is “Yes” as the clientsystems, respectively 102A, 102B and 102C are all within the firstdatacenter 104, and each frame 600, 700 and 750 indicates thedestination system is within the first cloud 108.

As such, switch 116 directs each frame from the received port 120 to theproper outbound port 122 to which is coupled the desired resource. It isalso understood and appreciated that switch 116 will remove the OSILayer 2 tags that are not expected, block 528. More specifically, if theclient system is employing a VLAN and has employed use of a Q Tag, thatQ Tag will remain, but the additional OSI Layer 2 tags applied by MTDC100 are removed at the time of delivery, such that the physical orvirtual resource in the cloud receives the frame in expected form, block530.

FIG. 8 illustrates a frame as between Cr, client system 202 (havingorigin MAC address f3:98:19:ab:55:b4), and physical cloud system 110D(having destination MAC address 09:19:20:07:05). It is also appreciatedthat client system 202 is in second datacenter 204 and physical cloudsystem 110D is in first cloud 108. Frame 800 has the same basicstructure as frame 600, a preamble 802, destination MAC 804, origin Mac806, a payload 808 and a gap sequence 810. For frame 800 the payload 808is “Dopey”.

Client system 202 has been assigned C series tags as demonstrated byTag1 812, Tag2 814 and Tag3 816. Tag3 816 is identifying the datacenterhaving the resource, specifically the first datacenter 108. For at leastone embodiment the additional OSI Layer 2 tag identifying thedatacenter, e.g., Tag3 816 is a VPLS tag.

Returning to decision 526, in the event that it is determined that theresource is not in the current cloud, as in the case of frame 800,method 500 proceeds to add appropriate OSI Layer 2 tagging to identifythe datacenter containing the resource, block 532. The frame, e.g.,frame 800, is then directed to the proper cloud, block 534.

With respect to FIG. 2, it is appreciated that frame 800 is providedfrom switch 212, to switch 222, to switch 220, and finally to switch116, and that that switch 116 will remove the OSI Layer 2 tags that arenot expected, block 528.

Again as noted above, in at least one embedment existing networkprovider connections may be used to interconnect different datacenters.In FIG. 8 frame 800′ represents the additional OSI Layer 2 tagging thatmay be applied in at least one embodiment to enable use of the existingnetwork connections as shown in FIG. 3. In addition to Tag3 identifyingthe datacenter, Tag4 818 has been added to identify the long haulnetwork IP. For at least one embodiment the additional OSI Layer 2 tagidentifying the network IP, e.g., Tag4 818 is a MPLS tag.

Moreover, for this optional use of an existing long haulinterconnection, method 500 adds a fourth OSI Layer 2 tag to identifythe network IP, block 536, and the frame is transferred from onedatacenter to another. In at least one embodiment the addition of thisfourth OSI Layer 2 tag is performed by router, e.g., router 302 in FIG.3, and then removed by router 300, such that the layer 3 transfer isentirely transparent, block 538.

Once again it will be appreciated that the use of Layer 2 tags selectedfrom the group consisting of, but not limited to, Q tags, QinQ tags,MPLS tags, VPLS tags, Segment ID tags, Global VLAN tags, is understoodas exemplary for one or more embodiments, and not as limitations. Indeedother current and developing protocols that permit Layer 2 extension areunderstood and appreciated to fall within the present teachings forLayer 2 tagging.

With the frame delivered, the method 500 moves to decision 540 and thequery of whether to continue or not. When the system remains active,MTDC 100 awaits new data, block 542, which may be in the form of a newclient VLAN being added, a new frame from a client system, or a newframe from an extended resource within the cloud. Indeed, although theabove description has been presented for the progression of a frame froma client system to a resource within the cloud, it is understood andappreciated that generally the same process is performed to transfer aframe from an extended resource within the cloud to an associated clientsystem. Moreover, with respect to frame 600, interchanging the originMAC address and 604 and the destination MAC address 606 would provide aframe for transfer from system 110A in the first cloud 108 to clientsystem 102A.

To summarize, for at least one embodiment, a method of providing MTDC100 consists of establishing within a first datacenter 104 a first cloud108 having first physical resources and first virtual resources andestablishing within a second datacenter 204 a second cloud 208 havingsecond physical resources and second virtual resources. The first cloud108 and the second cloud 208 are coupled together by OSI Layer 2.

Further, for at least one embodiment, this method of providing MTDC 100is enhanced by disposing a plurality of physical client systems, e.g.,102 and 202 in one or both of the first datacenter 104 and the seconddatacenter 204, each physical client system having a set of physicalinfrastructure resources 106, 206. The method continues by coupling eachphysical client system, 102, 202 to the coupled first and second clouds108, 208 by OSI Layer 2, the coupled cloud computing environment therebyvirtually extending the physical infrastructure resources 106, 206 ofeach physical client system 102, 202.

With respect to the above description of MTDC 100, multiple instances ofMTDCs, and methods 400 and 500 it is understood and appreciated that themethod may be rendered in a variety of different forms of code andinstruction as may be used for different computer systems andenvironments. To expand upon the initial suggestion of client systems102 and cloud systems 110, FIG. 9 is a high level block diagram of anexemplary computer system 900. Computer system 900 has a case 902,enclosing a main board 904. The main board 904 has a system bus 906,connection ports 908, a processing unit, such as Central Processing Unit(CPU) 910 with at least one microprocessor (not shown) and a memorystorage device, such as main memory 912, hard drive 914 and CD/DVD ROMdrive 916.

Memory bus 918 couples main memory 912 to the CPU 910. A system bus 906couples the hard disc drive 914, CD/DVD ROM drive 916 and connectionports 908 to the CPU 910. Multiple input devices may be provided, suchas, for example, a mouse 920 and keyboard 922. Multiple output devicesmay also be provided, such as, for example, a video monitor 924 and aprinter (not shown). As computer system 900 is intended to beinterconnected with other computer systems in the MTDC 100 a combinedinput/output device such as at least one network interface card, or NIC926 is also provided.

Computer system 900 may be a commercially available system, such as adesktop workstation unit provided by IBM, Dell Computers, Gateway,Apple, or other computer system provider. Computer system 900 may alsobe a networked computer system, wherein memory storage components suchas hard drive 914, additional CPUs 910 and output devices such asprinters are provided by physically separate computer systems commonlyconnected together in the network. Those skilled in the art willunderstand and appreciate that the physical composition of componentsand component interconnections are comprised by the computer system 900,and select a computer system 900 suitable for one or more of thecomputer systems incorporated in the formation and operation of MTDC100.

When computer system 900 is activated, preferably an operating system926 will load into main memory 912 as part of the boot strap startupsequence and ready the computer system 900 for operation. At thesimplest level, and in the most general sense, the tasks of an operatingsystem fall into specific categories, such as, process management,device management (including application and user interface management)and memory management, for example. The form of the computer-readablemedium 928 and language of the program 930 are understood to beappropriate for and functionally cooperate with the computer system 900.

Moreover, variations of computer system 900 may be adapted to providethe physical elements of one or more components comprising each clientsystem 102, the one or more components comprising the system 110supporting the cloud environment, the switches, routers and such othercomponents as may be desired and appropriate for MTDC 100.

It is to be understood that changes may be made in the above methods,systems and structures without departing from the scope hereof. Itshould thus be noted that the matter contained in the above descriptionand/or shown in the accompanying drawings should be interpreted asillustrative and not in a limiting sense. The following claims areintended to cover all generic and specific features described herein, aswell as all statements of the scope of the present method, system andstructure, which, as a matter of language, might be said to falltherebetween.

What is claimed is:
 1. A multi-tenant datacenter, comprising: aplurality of physical client systems in a first datacenter each physicalclient system having a set of physical infrastructure resources; and afirst cloud computing environment established in the first datacenter,and coupled to the physical client systems by OSI Layer 2, prior to anOSI Layer 3 connection, as the physical connection of a data channel forthe transfer of data frames, each frame having a plurality of OSI Layer2 tags permitting at least two client systems to have overlapping VLANsand or overlapping IP address ranges, the first cloud computingenvironment thereby virtually extending the physical infrastructureresources of each physical client system, wherein the OSI Layer 2 tagsare selected from the group consisting of Segment ID Tags and GlobalVLAN Tags.
 2. The multi-tenant datacenter of claim 1, further includingat least one OSI Layer 2 tag for identification of a datacenter.
 3. Themulti-tenant datacenter of claim 1, further including at least one OSILayer 2 tag for identification of a network IP address for a remotedatacenter.
 4. The multi-tenant datacenter of claim 1, wherein at leastone second cloud computing environment established in at least onesecond datacenter is coupled to the first datacenter by OSI Layer
 2. 5.The multi-tenant datacenter of claim 4, wherein the second cloudcomputing environment is indistinguishable from the first cloudcomputing environment by the plurality of physical client systems. 6.The multi-tenant datacenter of claim 4, further including at least oneentirely virtualized client system within the combined first and secondcloud computing environment.
 7. The multi-tenant datacenter of claim 4,wherein a plurality of second physical client systems each having a setof physical infrastructure resources are disposed in the seconddatacenter and coupled to the second cloud computing environment by OSILayer 2, at least one second physical client systems further utilizing aresource of the first cloud computing environment in the firstdatacenter.
 8. A method for providing a multi-tenant datacenter,comprising: establishing within a first datacenter a first cloudcomputing environment; locating at least one physical client system inthe first datacenter, each physical client system having a set ofphysical infrastructure resources; and coupling the at least onephysical client system to the first cloud computing environment by OSILayer 2, prior to an OSI Layer 3 connection, as the physical connectionof a data channel for the transfer of data frames, each frame having aplurality of OSI Layer 2 tags permitting at least two client systems tohave overlapping VLANs and or overlapping IP address ranges, the OSILayer 2 coupling virtually extending the physical infrastructureresources of each physical client system, wherein the OSI Layer 2 tagsare selected from the group consisting of Segment ID Tags and GlobalVLAN Tags.
 9. The method for providing a multi-tenant of claim 8,wherein at least one second cloud computing environment established inat least one second datacenter is coupled to the first datacenter by OSILayer
 2. 10. The method for providing a multi-tenant of claim 9, whereinthe second cloud computing environment is indistinguishable from thefirst cloud computing environment.
 11. The method for providing amulti-tenant of claim 9, further including at least one entirelyvirtualized client system within the combined first and second cloudcomputing environment.
 12. The method for providing a multi-tenant ofclaim 9, wherein a plurality of second physical client systems eachhaving a set of physical infrastructure resources are also establishedin the second datacenter and coupled to the second cloud computingenvironment by OSI Layer 2, at least one second physical client systemsfurther utilizing a resource of the first cloud computing environment inthe first datacenter.
 13. The method for providing a multi-tenant ofclaim 8, wherein the coupling of the at least one physical client systemand the first cloud computing environment by frames permits uniqueidentification for each client system of at least a host and a customer.14. The method for providing a multi-tenant of claim 8, furtherincluding at least one OSI Layer 2 tag for identification of adatacenter.
 15. The method for providing a multi-tenant of claim 8,further including at least one OSI Layer 2 tag for identification of anetwork IP address for a remote datacenter.
 16. The method for providinga multi-tenant of claim 8, wherein each frame provided by a clientsystem does not contain an IP address for a resource within the firstcloud computing environment.
 17. A method for providing a multi-tenantdatacenter, comprising: establishing within a first datacenter a firstcloud computing environment; locating a plurality of physical clientsystems in the first datacenter, each physical client system having aset of physical infrastructure resources; and uniquely identifying Layer2 data traffic as between each client system and the first cloudcomputing environment over the physical connection of a data channel forthe transfer of data frames distinct from the transfer of packets of anetwork layer, each frame having a plurality of OSI Layer 2 tags asunique identifiers permitting unique identification for each clientsystem of at least one host and a customer, the OSI Layer 2 tagspermitting at least two client systems to have overlapping VLANs,wherein the OSI Layer 2 tags are selected from the group consisting ofSegment ID Tags and Global VLAN Tags.
 18. The method for providing amulti-tenant of claim 9, wherein the first cloud computing environmentthereby virtually extends the physical infrastructure resources of eachphysical client system
 19. The method for providing a multi-tenant ofclaim 9, further including unique identification of a datacenter. 20.The method for providing a multi-tenant of claim 9, further includingunique identification of a network IP address for a remote datacenter.21. A method for providing a multi-tenant datacenter, comprising:establishing within a first datacenter a first cloud computingenvironment having first physical resources and first virtual resources;establishing within a second datacenter a second cloud computingenvironment having second physical resources and second virtualresources; and coupling the first cloud computing environment to thesecond cloud computing environment by OSI Layer 2 as the physicalconnection of at least one data channel for the transfer of data framesdistinct from OSI Layer 3 network layer traffic, each frame having aplurality of OSI Layer 2 tags permitting at least two systems utilizingthe coupled first datacenter and second data center to have overlappingVLANs, wherein the OSI Layer 2 tags are selected from the groupconsisting of Segment ID Tags and Global VLAN Tags.
 22. The method forproviding a multi-tenant of claim 18, further comprising: disposing aplurality of physical client systems in one or both of the firstdatacenter and the second datacenter, each physical client system havinga set of physical infrastructure resources; and coupling each physicalclient system to the coupled first and second cloud computingenvironment by OSI Layer 2 as the physical connection of a data channelfor the transfer of data frames, each frame having a plurality of OSILayer 2 tags, the coupled cloud computing environment thereby virtuallyextending the physical infrastructure resources of each physical clientsystem.